Various kinds of pitcher type water purifiers have hitherto been proposed which can purify a relatively large amount of raw water of approximately 1 to 2 liters at one time, which can be kept in custody in, for example, a refrigerator, and which is formed with a pouring opening from which water is poured into a cup.
For example, a pitcher type water purifier that is disclosed in Japanese Patent Application Laid-Open No. H-11-319799 is constructed in the way the water purifier has a casing having a pouring opening and a handle and the interior thereof is partitioned into upper and lower parts, as a raw water reservoir portion and a purified water reservoir portion, with a partition wall, a part of that has openings, being interposed between the both portions. And, on the bottom portion of the raw water reservoir portion, a circular-columnar purification cartridge is disposed in the way of being replaceable and in a state where the cartridge as a whole is kept projecting into the purified water reservoir portion. The purification cartridge has a raw water inlet shaped like a mesh at its upper part and has a purified water outlet shaped like a mesh at its bottom part, and activated carbon and/or ion-exchange resin are filled in its interior as adsorbent. In some cases, in place of ordinary activated carbon, antibacterial activated carbon is filled.
In the above-described pitcher type water purifier, the raw water that has been supplied into the raw water reservoir portion at the upper part of the casing is passed through the purification cartridge under a water pressure that corresponds to its own weight. At this time, through the action of adsorbent such as activated carbon, ion-exchange resin, and the like, organic substances such as residual chlorine, chlorinated odor, mold odor, and trihalomethane, and impurities such as heavy metal or aluminum, which are contained in the raw water, are eliminated, whereby the water is purified. Thereafter, the water is stored into the purified water reservoir located at the lower part.
However, as the conventional pitcher type water purifiers, there is only a type wherein adsorbent such as activated carbon or ion-exchange resin filled in the purification cartridge eliminates, due to the action of adsorption, etc., the chemical substances in the raw water. Further, in the purification cartridge, for the purpose of preventing such adsorbent from flowing out into the outside thereof, a main body thereof is constructed in the form of a mesh and in addition a filtering material with coarse mesh such as non-woven fabric is disposed therein. For that reason, conversely, bacteria or microbes are likely to propagate themselves. The conventional water purifier could not eliminate substances even up to such very fine substances.
Ordinarily, in the water of the public water line, in order to prevent the bacteria contamination, there is added thereto chemicals such as chlorine, as disinfectant that has strong sterilizing effect, less harm to the human body, and a high residual effect. Thereby, that water is managed. However, it is the point in time when it has been just supplied from the tap. In contrast to this, in the case of a pitcher type water purifier, according to the use thereof, there is also a case where it is stored in a refrigerator for a long period of time such as one week or so. Therefore, although it is stored as low-temperature storage, in a case where residual chlorine is eliminated by adsorbent such as activated carbon and as a result a minute amount of bacteria or microbes exist in the water having had the sterilizing effect lost, the following possibility exists. Namely, during such storage, such bacteria or microbes will propagate themselves and, in some cases, they will have propagated themselves up to the concentration that has effect upon the human body.
In order to eliminate those bacteria or microbes as well, as in the case of, for example, a cup-type portable water purifier disclosed in Japanese Utility Model Application Laid-Open No. H-5-15993 or an ordinary directly-connected-to-tap type water purifier, filling a hollow fiber membrane within a purification cartridge and thereby filtering such bacteria or microbes through the use of that hollow fiber membrane are effective.
By the way, in the hollow fiber membrane, in terms of its structure, in a case where the water pressure is low, the water passage rate is very low. Therefore, conventionally, as in the case of the cup-type water purifier disclosed in the said Japanese Utility Model Application Laid-Open No. H-5-15993, the use of it was limited to the cases where the amount of water that is to be purified at one time was small and, also, as in the case of the directly-connected-to-tap water purifier, the use of it was limited to the case where the water pressure from the tap was utilized.
However, the pitcher type water purifier purifies such a relatively large amount of water as to an extent of 1 to 2 liters or so, or at least 500 milliliters or so. In addition, the pressure of that water is only the weight alone of the raw water, itself, that is stored in the raw water reservoir portion that is located at the upper part. For that reason, in the case of having filled the hollow fiber membrane into within the purification cartridge of the above-described pitcher type water purifier, the time for processing the water becomes very long. In the case of the pitcher type water purifier in which using it immediately after supply of the water is also taken into account, the demerit that a long time is needed for purification processing is a very serious problem.
The present invention has been achieved in order to solve the above-described problems and has an object to provide a pitcher type water purifier and a purification cartridge for use therewith, which can purify a relatively large amount of raw water, that is to an extent of at least 500 milliliters or so, in a short period of time, which purifier and cartridge not only adsorb and eliminate organic substances such as residual chlorine, chlorinated odor, mold odor and trihalomethane, and impurities such as heavy metal and aluminum, but also 0.1 μm or more of very fine particles including bacteria or microbes and, even when storing the purified water for a long period of time, can prevent bacteria or microbes from propagating themselves and therefore can ensure a purification performance of high safety in terms of sanitation.